The air gap technology, as described in U.S. Pat. Nos. 5,797,415 and 6,000,420, which are owned by the Horizon Resources Corporation also and which is hereby incorporated by reference, discloses the significant advantages of using entrapped air as a thermal insulating barrier in the insulation of piping systems. The entrapped or xe2x80x9cstillxe2x80x9d air technology may be accomplished in several ways that provide the multiple layers of xe2x80x9cstillxe2x80x9d air enclosed in an opaque, clear or translucent material such as plastic. When using a clear or translucent material, the insulation system provides the added advantage of being able to evaluate the condition of the pipe or insulating system without removal of the insulation.
The first generation of the inventive insulation comprised a series of ridged multi-lumen extrusions that would be xe2x80x9cclippedxe2x80x9d, xe2x80x9clockedxe2x80x9d or xe2x80x9csnappedxe2x80x9d together, then placed over the pipe and installed by a final xe2x80x9csnapxe2x80x9d to complete the installation.
The invention incorporates a design that provides the same or similar insulation characteristics as that achieved in our previous patents. The jacket uses a core that could be extruded, thermoformed or pressed, just to name a few methods. The geometry of the inner core is constructed such that different pipe diameters can be handled with one or two designs rather than needing a separate core for each pipe size. One core design uses a relatively thin (0.010/0.020 inches) plastic xe2x80x9cfilmxe2x80x9d to form the core rather than the typical profile extrusion which is three to four times thicker, as shown in FIG. 6. The thinner core design reduces the material needed in the manufacturing process and makes the core more flexible. A plastic sheet or cover is used with the core to form the jacket. The cover also can be made thinner (0.020-0.025 inches) than the corresponding element of the previous designs. This smaller thickness allows this design to more easily meet the low smoke requirements for a fire situation in the industry. The cover and the core can be made from fire retardant polycarbonate plastic. The cover could be made of fire retatdant polycarbonate and the core could be made of polyvinlychloride.